The present invention relates to a system for feeding at least one bulk material and comprising at least one device for storing the material, such as a container or bin, furthermore a conveyor channel operatively connected with said storing device, and a conveyor member adapted for conveying along said conveyor channel bulk material arriving from said storing device into said conveyor channel. Systems of this kind are widely used in the plastics industry in conjunction with continuous and intermittent production processes in which bars, pipes, sheets, foils, plates and the like are produced by extrusion, calendering, rolling and/or coating, and/or formed parts are produced by injection molding. The feeding system or equipment may be used to supply production machines continuously or in batches with one or more plastic material components provided as granulates. Such feeding equipment or apparatus is frequently used to feed and mix two or more different granulates to a production machine or to a device located in front of such machine, for example to a device comprising stirring apparatus. In such a case the bulk material may be supplied in the form of granulated plastic material to which an additive also provided in the form of granulated material is then added. Such additive may be a dyestuff or another material adapted for influencing mechanical strength or other physical or chemical properties. Feeding and mixing equipment of this type may be used not only for processing plastics, but also for producing other types of goods such as fertilizers, plant protecting materials, other chemical and pharmaceutical substances and foods. The feeding method may be volumetric or gravimetric. If the feeding is volumetric, granulates supplied per unit of time are determined from volume output values of the conveyor members. If, on the other hand, the feeding is gravimetric, then the decreases in weight of the material disposed inside the storage devices are determined by weighing said storage devices containing the granulates, and perhaps by using feedback control for achieving predetermined values.
Attention is called here to the fact that the terms "at least one bulk material", "at least one storage device", etc., as used throughout the Specification and the Claims are intended to refer to one or more of the respective items. The term "each" as used, for example, in "each conveyor channel" is intended to be interpreted as addressing a "conveyor channel".